1. Field of the Invention
The present invention relates generally to compound aircraft and, more particularly, to a lift rotor system and bladelet stowage system for a compound aircraft having at least one circular disk structure.
2. Description of Related Art
The present invention relates to certain improvements made to an autogyro as disclosed and shown in U.S. Pat. No. 4,913,376, which is owned by the inventor of the present invention and is hereby incorporated by reference. As seen therein, the autogyro incorporates a pair of closely spaced, rigid counter-rotating circular planform wings or disk structures which each includes a plurality of rotor bladelets spaced peripherally thereabout. The disk structures are gimbal mounted above a fuselage for the autogyro and includes a drive system for providing power transfer from a propulsion engine to the disk structures.
With respect to the drive system disclosed in the '376 patent, it will be noted that it is a high speed/low torque belt driven system which translates into low speed/high torque at gearing associated with the lower disk. This increases the stress and therefore the requirements on such gearing and related components. Moreover, the drive components are subject to movement permitted by the gimbal mounting which creates certain undesirable strains on such a belt-type drive system. Accordingly, it has been found that the previous belt driven system, while functional, is not as robust and reliable as desired.
Further, it has also been found desirable for an aircraft to be operational in both a rotary wing mode and a fixed wing mode (also known as a "compound aircraft"). In this way, the aircraft can be flown in a rotary wing mode for take-off and landing, but in the fixed wing mode during flight once an appropriate altitude and speed have been attained.
Accordingly, it is a primary object of the present invention to provide a robust drive system for a compound aircraft which increases reliability in such aircraft.
It is another object of the present invention to provide a drive system for a compound aircraft which is more rugged in design, whereby the components undergoing high torque are minimized.
It is still another object of the present invention to provide a drive system for a compound aircraft which is better able to accommodate movement associated with gimbal mounting of the rotor with the aircraft.
Yet another object of the present invention is to provide a drive system for a compound aircraft which is positioned outside the fuselage thereof so as to reduce noise within the cockpit of the aircraft.
Still another object of the present invention is to provide a stowage system for the bladelets with respect to the disk structures so the aircraft may be operated in both rotary and fixed wing mode.
Another object of the present invention is to provide safeguards within the bladelet stowage system so as to have the bladelets associated with each disk move in unison and be located in similar position with respect to the disk periphery.
These objects and other features of the present invention will become more readily apparent upon reference to the following description when taken in conjunction with the following drawings.